This study will attempt to gather information on the epidemiology, bacteriology, immunology and clinical aspects of Group A and Group B streptococcal infections. The significance of carriage at different sites, serological responses, antigenic changes, resident bacteriophages, presence of streptococci on normal skin and persistence of streptococci in skin lesions will be explored. The possible applications of these studies as preventive measures will be evaluated. BIBLIOGRAPHIC REFERENCES: Wannamaker, L.W. and Ferrieri, P.: Streptococcal infections - Updated. Disease-A-Month, H.F. Dowling, ed., Year Book Medical Publishers, Inc. Chicago, October 1975. Brown, J., Wannamaker, L.W. and Ferrieri, P.: Enumeration of beta-haemolytic streptococci on normal skin by direct agar contact. J. Med. Microbiol., 8:503-512, 1975.